Touch display device including buffer layer for accuracy of touch sensing

Abstract

A touch display device includes a display panel, a conductive layer, an optical matching layer and a buffer layer. The display panel comprises a first substrate, a second substrate and a display medium layer. The first substrate comprises a first surface and a second surface, the second substrate is disposed opposite to the first substrate, and the display medium layer is disposed between the second surface of the first substrate and the second substrate. The conductive layer is disposed on the first surface of the first substrate, and comprises a plurality of sensing electrodes. The optical matching layer is disposed between the conductive layer and the first surface of the first substrate. The buffer layer with a thickness greater than or equal to 50 Å and less than or equal to 3000 Å is disposed between the optical matching layer and the first surface of the first substrate.

What is claimed is: 
     
       1. A touch display device, comprising:
 a display panel, comprising:
 a first substrate including a first surface and a second surface; 
 a second substrate disposed opposite to the first substrate; 
 a display medium layer disposed between the second surface of the first substrate and the second substrate; and 
 a color filter layer disposed between the second surface of the first substrate and the display medium layer; 
 
 a conductive layer disposed on the first surface of the first substrate, wherein the first substrate is disposed between the conductive layer and the second substrate, and the conductive layer comprises a plurality of sensing electrodes; 
 an optical matching layer disposed between the conductive layer and the first surface of the first substrate, wherein the optical matching layer includes a flat surface, and the plurality of sensing electrodes are disposed on the flat surface; and 
 a buffer layer disposed between the optical matching layer and the first surface of the first substrate, wherein a thickness of the buffer layer is greater than or equal to 50 Å and less than or equal to 3000 Å, the buffer layer directly contacts the first surface of the first substrate, and a material of the buffer layer comprises silicon dioxide, 
 wherein the first substrate comprises a first side and a second side opposite to the first side, the conductive layer, the optical matching layer and the buffer layer are disposed on the first side of the first substrate, and the color filter layer and the display medium layer are disposed on the second side of the first substrate, 
 wherein the optical matching layer is directly contacted with the plurality of sensing electrodes and the buffer layer. 
 
     
     
       2. The touch display device of  claim 1 , wherein a thickness of the optical matching layer is greater than or equal to 100 Å and less than or equal to 1000 Å. 
     
     
       3. The touch display device of  claim 1 , wherein the optical matching layer comprises a first sub-layer and a second sub-layer, the first sub-layer is disposed between the buffer layer and the second sub-layer, and a refractive index of the first sub-layer is greater than a refractive index of the second sub-layer. 
     
     
       4. The touch display device of  claim 3 , wherein a material of the first sub-layer comprises niobium pentoxide. 
     
     
       5. The touch display device of  claim 3 , wherein a material of the second sub-layer comprises silicon dioxide. 
     
     
       6. The touch display device of  claim 1 , wherein a material of the first substrate comprises aluminum silicate. 
     
     
       7. The touch display device of  claim 1 , wherein the display panel further comprises a transistor layer disposed between the second substrate and the display medium layer. 
     
     
       8. The touch display device of  claim 1 , wherein the display medium layer comprises a liquid crystal layer, an organic light emitting diode element layer or an inorganic light emitting diode element layer.